RP via router/hub or directly connected?
Can you connect to RP at all? (Web browser etc)
For direct connection and if using Pavel's Alpine Image the Red Pitaya IP address is 192.168.1.100, via router/hub the RP should receive an IP via DHCP.
You have to start the "HPSDR-compatible SDR transceiver" via the web interface.
Which PowerSDR version do you use?
If you're using a plain RP (not a C25, HAMlab), I recommend https://github.com/TAPR/OpenHPSDR-Power ... tag/v3.4.9 and set it to HERMES!